Electric meter.



Np. r568,932. PATENTE!) AUG. 30, 1994.

"1'. DUNGAN.

ELECTRIC METER.

,'LXELTIOH'TILED JULY' 1l,A 1901. H0 HODEL. 3 SHEETS-SHEET Mm Ww #NWN Triangel; un

3 SHEETS-485251 2.

:35e UF?- 'Tx-m (s) u P DE EYE- ,PATENTBD AUG. 30, 1904.

T. msnm. mgmt-.1c METER.

unieuro: r

to nonni.

YUM www Nfl-E55 E PATEBTBD AUG. 3U, 1904.

T. DUNCAN. ELECTRIC METER.

urucnw rILzn :nu 11. mu.'

l0 XODBL,

-a wattmeter.

of current 1. Ysupplying current to transmisl sion-mains that convey the sume to transhating devices 3. A resistance -l suliiciently high to divert current through the mainarmature\vinding 5 is employed. This armatnre-v.'intling :3 is of low resistance and is prefi erably wound in the fashion shown and is -supported by an aluminium cup constituting also a damping element 6. rl-he armaturewinding 5 is connected with the segments of t he comm 'uu-ttor T with which the commutatorbrushcs S 5 are connected, these brushes being connected with the terminals of the resistance -L An adjusting resistance 9 is provided for accurately determining the strength of thei field due to the said armature-winding. and l thereby the speed of the meter. A permanent magnet 1U is provided with poicpieces il1 11, constructed, preferably` of soft iron, `which pole-pieces are curved to coliform to the contour of the armature. To reduce the magnetic reluctance. between the poles of the permanent magnet. 1 prefer to employ a cy- 1 lindrical body of soft iron 12, that is stationarily mounted upon a brass yoke 13.Sccured l to the ends of the pernmncnt magnet. This cylindrical body of iron is provided with an axial bore, through which the meter shaft 14 extends, the meter-shaft being of course free from thecylindcr 12, but fixed with relation to the armature-winding 5 and the aluminium cup 6. The shaft 1-1 of the meter is mounted at its lower end upon a bearing 15, that may be vertically adjusted by a suitable adjustingscrew 16. the screw being secured within the sleeve of a support 17, mounted upon and extending beneath the yoke of non-magnetic material 13.

To provide for the necessa ry starting torque in the instrument. a supplemental armature winding 151l of high resistance is preferably provided. this supplemental winding being connected in bridge of the mains 2 2 through the agency of a commutator 19 and the commulator-brushes 20. An adjusting resistance. Q1 is included in series with the commutator brushes 2|) and the starting armature-winding 18 for the purpose of determining the torque of the armature-winding 18 that is necessary to overcome friction.

`o preserve the uniform strength of the permanent magnet, 1 prefer to employ a winding subject to the pressure in the system, the winding being prefcrabLv subdivided into two coils 2'2 22, each inclosing a limb of the magnet.

, 'hile the coils 22 Z2 are possessed of the requisite number of turns to maintain the proper magnetism in the permanent magnet, they are not strong enough to alter the nature of the metcrwthat is, they are not adapted nor so located as to transform the meter into l i t 'ilo 4prevent the.. resistance 4 from reacting magnetically upon the motor element of the resistance andthe motor clement of the meter.

f the shield being preferably in the form of an iron tube completely inclosing the'resistance.

I have illustrated an indicating-dial upon which the ampere-hours may be read; but l have not deemed it essential to illustrate the mechanism for actuating the indexes of the reading-dial, as this is well understood by those skilled in the art.

The motive power of the, meter is developed by the armature-winding 5 and the permanent magnet 10 and is proportional to the resist-v ance 4 and the current traversing the latter. The drag upon the armature lis obtained' by means of the damping element- 6, which by being within the field of the permanent magnet and secured to the shaft of the met# r produces the necessary modification in the speed of the said shaft. The starting torque is produced' by the. coin-rat-ive relation of the supplemental high-resistance winding 18 with the permanent. magnet.

I have herein shown and particularly described the preferred embodiment of my invention; but it is obvious that changes may be made without depart-ing from the. spirit thereof, and I do not, therefore, wish to he limited to the precise disclosure herein set forth; but, A

Having thusdescribcd my invention, I claim as new and desi re to secure by Letters Patent- 1Q In asystcm of electrical distribution, the combination with a eurrenbgenerator, of a Coulomb-me'. er. havinga mainarmatu re-winding subjectto the current in the system, a supplemental armature-winding subject to the pressure of the syst-cm, and means for producing a magnetic field within which the said armature-windings are located, substantially as described.

2. In a system of electrical distribution, the combination with a current-generator, of a. Coulomb-meter having a main armaturcwind ing subject to the current in the system, a supplemental armature-winding subject to the pressure of the system, and a permanent magnet for producing a ticld within which the said armature-windings are located, substantially as described. I

3. In a System of electrical distribution, the combination with a current-generator, of a. coulomb-meter having a main armature-winding subject to the current in the system, a supplemental armature-winding subject to the pressure of the system, means for producing a magnetic field within which the said armature-windings are located, and a body 12 of magnetic material inelosed by the armaturewindings, substantially as described.

4. In a system of electrical distribution, the combination with a current-generator, of a Coulomb-meter havinga main armature-windmg subject to the current in the system, asu p- ICO IIO

'roepen presure of the system, n permanent magnet for producing a field within which the said armatnredvincling are located, and Vu body 12 of magnetic material incloscd by the arma-v tu re-wimi ings, 4snlftalfxtiztlly as dcecrihed.

5. in a system of electrical distribution, the cuml'iinntio'n with a. currcntfgenerator, 'of a Coulomb-meter having a main armature-winding subject to the cu rrcnt in the system., a supplen'enmi armaturwinding for furnishing an initial starting torque to compensate for-friction` and means for producing a. magnetic field within which the said arnmtu rewindings are located, substantially as described.

6. in acoulomb-metcr, the combination with means for producing a Reid of permanent strength, of an armature provided with a winding subject to the current in u system of disfrihuton, said, armature-winding boing in shunt of a restance in series with one of the mains of said system, and a tubular magnetic shield inclosing the saifl resistance to prevent lines of force thereof from nuencing the operation'of the mex-substnntially asdeecribed.

in witne whereof I hereunto subscribe my 25 name txia id clay of June` A. D. 1901.

THOMAS DUNCAN. Vitnesscsz- GEORGE: L. CRAGG, lhmnmc'r F. OBERGFELL 

